Composition and Antinociceptive Activity of the Essential Oil from <i>Protium Heptaphyllum</i> Resin

Abstract

The chemical composition of the essential oil from Protium heptaphyllum resin was analyzed by GC/MS and the oil examined for antinociceptive activity in chemical and thermal tests. Fourteen compounds were characterized, representing 95.8% of the total essential oil, with the monoterpenes α-phellandrene (10.4%), α-terpinene (13.7%) and 1,8-cineole (58.7%) as major components. Oral administration of the essential oil (50 and 100 mg/kg) significantly inhibited chemical nociception induced by capsaicin and formalin in mice. In rats, the oil also effectively enhanced the radiant heat-induced tail-flick latency response at a dose of 100 mg/kg. However, the essential oil, at either dose, was ineffective against thermal pain in the hot-plate test.